One in three Covid-19 survivors subsequently developed a neurological or psychiatric condition within six months of being infected, a new study has found.
Researchers at the University of Oxford analysed the TriNetX electronic 2020 health records of more than 230,000 coronavirus patients, mostly from the US.
Findings showed that contracting the virus is “robustly associated” with an increased risk of developing mental health and neurological conditions after diagnosis, with those who suffered with severe Covid-19 being the worst affected.
Increased mental health risk
The study, published in The Lancet Psychiatry journal, estimated that 34 per cent of people who survived coronavirus developed a mental or neurological condition within six months of infection.
For 13 per cent of people, it was their first recorded neurological or psychiatric diagnosis
Findings from the study, which is said to be the largest of its kind to date, also suggested that the incidence of such conditions rose with the severity of the Covid-19 infection.
A neurological or psychiatric diagnosis was recorded in 39 per cent of those who were admitted to hospital and 46 per cent among those in intensive care.
Meanwhile, such a diagnosis was recorded in as many as 62 per cent among those who had encephalopathy, described as “delirium and other altered mental states”, during their Covid-19 infection.
Taking into account underlying health characteristics, such as age, ethnicity and existing conditions, researchers also found that there was a 44 per cent greater risk of neurological and mental health diagnoses after Covid-19 compared with flu, and a 16 per cent higher risk than with other respiratory tract infections, such as pneumonia.
‘Urgent’ research needed
Researchers looked at the incidence of 14 neurological and mental health disorders among 236,379 patients over the age of 10 who were infected with Covid-19 on or after 20 January 2020 and who were still alive on 13 December that year.
This group was then compared with 105,579 patients diagnosed with influenza and 236,038 patients diagnosed with any respiratory tract infection, including influenza.
In the Covid-19 group, researchers found anxiety disorders occurred among 17 per cent of all patients, while 14 per cent developed mood disorders, seven per cent had substance misuse disorders and five per cent insomnia.
Meanwhile, the incidence of neurological conditions appeared lower, with 0.6 per cent having a brain haemorrhage, 2.1 per cent ischaemic stroke and 0.7 per cent dementia.
Given the scale of the coronavirus pandemic and chronic nature of some neurological and psychiatric diagnoses, researchers concluded that “substantial effects on health and social care systems are likely to occur”.
They argued that “urgent” research was needed to understand how and why such disorders occur and how they can be treated.
Paul Harrison, professor of psychiatry at the University of Oxford and the study’s lead author, said: “These are real-world data from a large number of patients. They confirm the high rates of psychiatric diagnoses after Covid-19, and show that serious disorders affecting the nervous system (such as stroke and dementia) occur too.
“While the latter are much rarer, they are significant, especially in those who had severe Covid-19.
“Although the individual risks for most disorders are small, the effect across the whole population may be substantial for health and social care systems due to the scale of the pandemic and that many of these conditions are chronic.
“As a result, health care systems need to be resourced to deal with the anticipated need, both within primary and secondary care services.”
Researchers noted that their study was limited by the unknown completeness and accuracy of the electronic health records and that the results may not apply to people who had Covid-19 but were not diagnosed with the illness.
The severity of the neurological and psychiatric disorders was also not known, nor whether patients recovered and what happened to them after six months.
Overall the authors concluded that Covid-19 does lead to a greater risk of neurological and psychiatric disorders when compared with flu and other respiratory tract infections, but there was no clear evidence this was the case for some conditions such as parkinsonism and Guillain-Barré syndrome.
Dr Max Taquet, a co-author of the study, added: “We now need to see what happens beyond six months. The study cannot reveal the mechanisms involved, but does point to the need for urgent research to identify these, with a view to preventing or treating them.”